Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method and a device for transmitting an uplink control signal in a wireless communication system.
Related Art
A frequency source is in a saturated state based on the current, and various technologies have been partially used in a wide frequency band. To this reason, in order to satisfy a higher demand quantity of the data transmission rate, as a method for ensuring a wide bandwidth, carrier aggregation (CA) has been introduced, which is a concept in which each of distributed bands is designed to satisfy basic requirements capable of operating an independent system and a plurality of bands is bound as one system. In this case, a band or a carrier which can be independently operated is defined as a component carrier (CC).
In recent communication standard, for example, standard such as 3rd generation partnership project (3GPP), long term evolution-advanced (LTE-A), or 802.16m, it is considered that the bandwidth is continuously extended up to 20 MHz or more. In this case, the wideband is supported by aggregating one or more component carriers. For example, when one component carrier corresponds to a bandwidth of 5 MHz, a bandwidth of maximum 20 MHz is supported by aggregating four carriers. As such, a system of supporting carrier aggregation is called a carrier aggregation system.
Meanwhile, the wireless communication system may use a transmit diversity when transmitting the uplink control signal. The transmit diversity means a technique of transmitting the same signal by using different antenna ports. One type of transmit diversity includes a spatially orthogonal resource transmit diversity (SORTD). The SORTD is a transmit diversity technique of transmitting the same signal simultaneously by assigning and using spatially orthogonal resources to different antenna ports. The transmit diversity may be also applied to a carrier aggregation system.
In the case of applying the transmit diversity to transmit the uplink control signal, which resource is assigned to a second antenna port, that is, an additional antenna port other than an antenna port (referred to as a first antenna port) used in single antenna port transmission becomes a problem. Particularly, when an acknowledgement/not-acknowledgement (ACK/NACK) signal representing acknowledgement for the data is transmitted by using the SORTD, which resource is applied to the second antenna port may become a problem.